Welding alloy



Patented June 10, 1930 UNITED STATES PATENT OFFICE ARTHUR R. LYTLE, OFELMHURST, NEW YORK, ASSIGNOR TO UNION CARBIDE & CAR- BON RESEARCHLABORATORIES, IN 0., A CORPORATION OF NEW YORK WELDING ALLOY 1T0Drawing.

My invention relates to fusion welding alloys, and particularly tocopper alloys for the welding or brazing of ferrous material parts. Y

has been found convenient in the art of 'autogenous welding to utilizecopper alloys, such as the bronzes or brasses for the purpose of joiningparts formed of ferrous materials. This has been a convenient we1d- 9ing method because of the good strength,

and ductility of the alloys as deposited, and

' the relatively low temperature of application of the welding material,as well as the ease and convenience with which it maybe applied. For theformation of a permanent weld, such alloys as the copper-zinc brasses orbronzes have been found quite satisfactory. However, when the weld mustbe remade a number of times, as where it to is desirable to separate theparts, after weldin and then re-weld, or particularly where it isdesired to build u repeatedly worn surfaces with a bearing ronze, thebronzes or brass alloys previously used have not been found entirelysatisfactory, because of the fact that they penetrate the ferrous basemetal for a considerable distance. This penetration appears to takeplace between the crystals, to form an inter-crystalline matrix, andappears to be atypical intermetallic corrosion such as occurs in anumber of alloys when in contact with other metals in the molten state.Themolten copper alloy appears to enter the steel and s read along thegrain boundaries to a considerable depth. Pure copper and many of itsalloys show this phenomenon, and the presence of tin appears toacceleratethe rate of dpenetration. It results in a destruction crackingof the surface ,layer of the ferrous part, producing a serious reductionin strength, which may lead to failure in service of the iron structure.

The process of welding with bronze is particularly applicable to thebuilding up 0 may be made by fusion welding of the Application filedDecember 20, 1929. Serial at. 241,453.

properties, and which may be convenientlyapplied by fusion weldingtoferrous material parts, without the occurrence of penetration or injuryto the surface or strength of the ferrous material part.

Other objects and details of my invention will be apparent from thefollowing descriptlon.

. I find that an alloy composed of copper, nickel, and zinc inappropriate'proportions has the desired properties. The nickel maysuitably comprise at least of. the alloy,

and the zinc not more than 20%, with the balance mainly copper. Such an.alloy. is well adapted to fusion welding.

If the alloy is to be repeatedly applied by fusion to the same ferroussurface, it is further desirable that the nickel be increased to atleast 30%, in order to avoid undesirable enetration and injury to thesurface of the f drrous part. To further increase the ease of welding,small quantities of silicon may also be added to the welding alloy.

A desirable alloy for the purpose abovementioned may be produced by thefollow ing list of materials added, within the indicated range ofcomposition. J

Nickel 15 to 60% Zinc si up to 25% Silicon up to 4% Manganese -Q.-- upto 4.00% Iron up to 4.00% Copper Balance.

The nickel of the alloy when in the molten state appears to absorb gasesfrom the surrounding atmosphere readily, and then ,at

the instant of solidification to throw them out of solution to formbubbles in the metal, weakening its structure. An alloy containingmainly copper, zinc and nickel is usable for welding purposes, butrequires great care and skill in the conduct of the welding o eration,to avoid the production ofa we d full of blowholes and orosity, andaccordingly weak and unsatis actory. I find, however, that the additionof a very small quantity of silicon, even as small an amount as 0.05%exerts a profound effect upon the characteristics of the alloy when inthe molten state, and during the transition from the molten to the solidstate. The exact mechanism of the effect is not apparent, but I findthat the use of the silicon removes the tendency of the metal todissolve ases, and eject them at the instant of solidi cation.

While I have shown but a limited number of embodiments of m invention itis ada ted to other modi cations therefrom wit out departure from thespirit thereof such and it is desired therefore that onl. limitationsshall be imposed upon t e appended claims as are indicated therein, orrequired by the prior art.

I claim as my invention:

1. A composite article comprising a fer- 7 rolls portion and a body ofreadily fusible copper-zinc-nickel alloy firmly welded thereto, saidalloy containing 25% to 60% of nickel; not more than 25% of zinc; and0.05% to 4% of silicon; with the remainder principally copper.

2. A composite article comprising a ferrous portion and a body ofreadily fusible copper-zinc-nickel alloy firmly welded thereto, saidalloy containing about 30% of nickel, about 20% of zinc, and about 0.05%of silicon, with the remainder principally copper.

In testimony whereof, I aflix my signature.

ARTHUR R. LYTLE.

